In a mobile communication network, wireless base stations are provided at spacing of around several hundred meters to several kilometers. Each of the wireless base stations establishes communication with a mobile terminal positioned in a narrow range called a wireless cell. In this manner, a service area that is wide two-dimensionally is achieved. The wireless cells have a variety of sizes and shapes, which are determined in overall consideration of a radio wave propagation characteristic, population in an area, a moving characteristic of the user, and the like.
In general, a wireless network control station is allocated to a group of several tens to several hundreds of wireless cells. The wireless network control station carries out transfer of user data with a core network, processing of outgoing and incoming calls with respect to a mobile terminal, processing of handover when a mobile terminal moves between wireless cells, transfer processing of a location registration message when a mobile terminal moves between location registration areas, and the like.
In order to efficiently operate the wireless network control station, a plurality of wireless cells to be contained are preferably selected in a manner that there is no significant bias generated in processing loads of a plurality of wireless network control stations. Hereinafter, a group of a plurality of wireless cells contained in the wireless network control station may be called a wireless cell group. In addition, in general, a processing load of handover between wireless cells belonging to different wireless network control stations tends to increase with respect to a processing load of handover between wireless cells belonging to the same wireless network control station. In order to prevent increase in a processing load of the wireless network control station, a plurality of wireless cells to be contained in one wireless network control station are desirably selected from wireless cells close to each other geographically.
Further, a configuration of a wireless cell group to be contained in a wireless network control station should be reviewed from every month to every year or so depending on environmental change of a radio wave propagation characteristic, change in demand, change in a moving characteristic of the user, and the like.
As a configuration management system of a wireless access network that achieves leveling of a processing load of the wireless network control station, there is a method of achieving dynamic load distribution in a manner that a load of the wireless network control station is monitored from an exchange of a core network during operation, and when the load exceeds a threshold value, calling processing is transferred to other wireless network control stations (for example, refer to Patent Document 1).
In addition, there suggested is a method of achieving leveling of a processing load of the wireless network control station in a manner that, in a wireless access network including a wireless network control device, a hub, and a wireless base station which are connected hierarchically, optimization of a hub level with the wireless base station as a unit and optimization of a wireless network control station unit with a hub as a unit are carried out repeatedly based on traffic demand of each wireless cell (for example, refer to Patent Document 2) In addition, there suggested is a method of changing a wireless cell configuration based on a measured traffic amount in order to level traffic in a wireless access network (for example, refer to Patent Document 3).
Patent Document 1: JP 2003-199136-A
Patent Document 2: Pamphlet of WO 02/35871
Patent Document 3: JP 2003-174665-A